why has the russian government banned adoptions by u.s. citizens? >>> and new revelations about ronald reagan's relationships with two of the most powerful women in the world, the queen and margaret thatcher in documents released three decades later. "nightly news" begins now. >>> from nbc news world headquarters in new york, this is "nbc nightly news" with brian williams. >>> good evening, i'm natalie morales in tonight for brian. it is down to the wire now with about 80 hours until the fiscal cliff deadline. and on what is a holiday weekend for many, that is not the case for congressional leaders in washington. there was a sense of urgency today as the president met with house and senate leaders along with the treasury secretary and vice president a short while ago at the white house to try and forge a last-minute deal. the president says he is optimistic, but at this hour, the fiscal cliff still looms. we begin our coverage with nbc's white house correspondent, peter alexander who has been watching the developments all day. peter, good evening to